// Copyright (c) 1996-99 The Regents of the University of California. All
// Rights Reserved. Permission to use, copy, modify, and distribute this
// software and its documentation without fee, and without a written
// agreement is hereby granted, provided that the above copyright notice
// and this paragraph appear in all copies.  This software program and
// documentation are copyrighted by The Regents of the University of
// California. The software program and documentation are supplied "AS
// IS", without any accompanying services from The Regents. The Regents
// does not warrant that the operation of the program will be
// uninterrupted or error-free. The end-user understands that the program
// was developed for research purposes and is advised not to rely
// exclusively on the program for any reason.  IN NO EVENT SHALL THE
// UNIVERSITY OF CALIFORNIA BE LIABLE TO ANY PARTY FOR DIRECT, INDIRECT,
// SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES, INCLUDING LOST PROFITS,
// ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN IF
// THE UNIVERSITY OF CALIFORNIA HAS BEEN ADVISED OF THE POSSIBILITY OF
// SUCH DAMAGE. THE UNIVERSITY OF CALIFORNIA SPECIFICALLY DISCLAIMS ANY
// WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
// MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. THE SOFTWARE
// PROVIDED HEREUNDER IS ON AN "AS IS" BASIS, AND THE UNIVERSITY OF
// CALIFORNIA HAS NO OBLIGATIONS TO PROVIDE MAINTENANCE, SUPPORT,
// UPDATES, ENHANCEMENTS, OR MODIFICATIONS.

package org.tigris.gef.presentation;

import java.awt.Color;
import java.awt.Graphics;
import java.awt.Point;
import java.awt.Polygon;

/** Draws a triangular arrow head at the end of a FigEdge */

public class ArrowHeadHalfTriangle extends ArrowHead {

    static final long serialVersionUID = -7257932581787201038L;

    public void paint(
            final Graphics g,
            final Point start,
            final Point end,
            final Color lineColor,
            final Color fillColor) {
        Point[] points = fetchCache(start, end);

        Polygon triangle = new Polygon();
        for (Point p : points) {
            triangle.addPoint(p.x, p.y);
        }

        Graphics graphics = (Graphics) g;
        graphics.setColor(fillColor);
        graphics.fillPolygon(triangle);
        graphics.setColor(lineColor);
        graphics.drawPolygon(triangle);
    }

    public Point[] getArrowPoints(Point start, Point end) {
        int xFrom, xTo, yFrom, yTo;
        double denom, x, y, dx, dy, cos, sin;

        xFrom = start.x;
        xTo = end.x;
        yFrom = start.y;
        yTo = end.y;

        dx = (double) (xTo - xFrom);
        dy = (double) (yTo - yFrom);
        denom = dist(dx, dy);
        if (denom == 0)
            return null;

        cos = getHeight() / denom;
        sin = getWidth() / denom;
        x = xTo - cos * dx;
        y = yTo - cos * dy;
        int x2 = (int) (x + sin * dy);
        int y2 = (int) (y - sin * dx);

        return new Point[] {
          new Point(xTo, yTo),
                new Point(xFrom, yFrom),
                new Point(x2, y2)
        };
    }

} /* end class ArrowHeadHalfTriangle */
